Ian White, G3SEK wrote:
>
> Ed wrote:
> >Just a little addendum...the prop pitches also came out of just about
> >every engine that GE or Pratt & Whitney ever built, not just from the
> >WW2 era. All the DC series up to the DC7, the Old Constallations, just
> >about any military recip built up until right now, and of course, the
> >civilian versions of any multi-engine aircraft. US FARs require that
> >a "means be available to rotate the propeller to a 90 degree position
> >in the event that engine fails." Don't take that as an exact quote..
> >
>
> I'd heard that modern prop pitch actuators are mostly hydraulic, so the
> supply of electric motors may be limited.
>
> Little cousin from the WW2 era was the cowl gill motor, which is a
> similar cylindrical epicyclic unit, but much smaller, originally
> intended for opening and closing the cooling slats on aero engines.
>
> It's too small for HF beams, unless you use it to drive through a car
> starter reduction gear. If the diameter and weight are not a problem
> (eg if you rotate the whole tower from ground level) starter gears and
> flywheels are a nice cheap way to generate a lot of torque and braking
> power.
>
> 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
> 'In Practice' columnist for RadCom (RSGB)
>
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This is a minor correction about what had prop pitch motors. The only
Civilian plane to use them was a C-46 with special certification. The
prototype DC-6 had them but had to be removed. All of the
Connies/Dc-6,7,5,3,&2 had Hamilton Standards which were Hydramatics.The
B-29,B-24,C-46,C-87 Martin B-26 some early versions. The connections on
the motor are D decrease I increase G ground F feather. DIGF Did I get
F-----D for rememberinf the hook up.
Hank KN6DI
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